Fluorine-containing copolymer, process for its production and curable composition

ABSTRACT

A fluorine-containing copolymer having fluidity at room temperature and comprising, based on entire polymer units, from 20 to 70 mol % of polymer units (1) derived from a polyfluoroolefin and from 1 to 80 mol % of polymer units (2) having a polyoxyalkylene chain having, at its terminal, a group selected from the group consisting of an active hydrogen-containing group, an epoxy group and a functional group cross-linkable by the action of moisture, the total of the polymer units (1) and the polymer units (2) being from 30 to 100 mol %.

This is a continuation of application Ser. No. 07/556,374, filed on Jul.23, 1990, now U.S. Pat. No. 5,096,989, which is a division of U.S. Ser.No. 07/354,197 filed May 19, 1989 now U.S. Pat. No. 5.073,613.

The present invention relates to a fluorine-containing copolymer, aprocess for its production and a curable composition.

Heretofore, in the field of sealing materials or coating materials, ithas been desired to develop a resin which is excellent in thestretchability and weather resistance and which is curable at roomtemperature. In recent years, in addition to such requirements, therehave been requirements for overcoatability and for solving a problem offormation of stain due to migration of a low molecular weight siliconeoil or plasticizer contained in the resin such as a silicone resin,which may otherwise fulfill the above-mentioned requirements.

For example, in the case of sealing materials, there has been adevelopment from a non-stretchable oily caulking material to an elasticurethane or polysulfide material. Further, a weather resistant siliconematerial has been developed. However, it has a drawback that thestaining due to allow molecular weight silicone oil is substantial.Under the circumstances, a modified silicone has been developed whereinthe backbone structure is a polyalkylene oxide, and siloxane linkagesare present only at the cross-linked sites. However, there still is acase where the weather resistance, etc. are inadequate, and such doesnot provide an adequate solution.

On the other hand, as a resin curable at room temperature having highweather resistance, a fluoroolefin-vinylether copolymer has been known,and it is used for a coating composition. The coating composition madeof such resin is excellent in the weather resistance and serves toincrease the durability of a building stricture, and its usefulness forindustrially application is being recognized.

However, a resin having higher flexibility is desired for application tosealing materials, elastomers, water-proofing material, adhesives, PCMcoating materials or elastic coating materials which require highstretchability in addition to the weather resistance as in the presentapplication. Further, from the viewpoint of practical application, acomposition of one-pack type is desired.

It is an object of the present invention to solve the above-mentionedproblems.

The present invention provides a fluorine-containing copolymer havingfluidity at room temperature and comprising, based on entire polymerunits, from 20 to 70 mol % of polymer units (1) derived from apolyfluoroolefin and from 1 to 80 mol % of polymer units (2) having apolyoxtyalkylene chain having, at its terminal, a group selected fromthe group consisting of an active hydrogen-containing group, an epoxygroup and a functional group cross-linkable by the action of moisture,the total of the polymer units (1) and the polymer units (2) being from30 to 100 mol %.

The present invention also provides a process for producing afluorine-containing copolymer, which comprises polymerizing afluoroolefin and a monomer having a polyoxyalkylene chain having, at itsterminal, a group selected from the group consisting of an activehydrogen-containing group, an epoxy group and a functional groupcross-linkable by the action of moisture and an α,β-unsaturated groupcopolymerizable with the fluoroolefin.

The present invention further provides a process for producing afluorine-containing copolymer having a polyoxyalkylene chain having ahydroxyl group at its terminal, which comprises adding an alkylene oxideto a fluorine-containing copolymer comprising, based on entire polymerunits, from 20 to 70 mol % of polymer units (1) derived from afluoroolefin and from 1 to 80 mol % of polymer units (3) having afunctional group to which the alkylene oxide is to be added, the totalof the polymer units (1) and the polymer units (3) being from 30 to 100mol %.

The present invention further provides a process for producing afluorine-containing copolymer having a functional group cross-linkableby the action of moisture, which comprises reacting afluorine-containing copolymer comprising, based on entire polymer units,from 20 to 70 mol % of polymer units (1) derived from a fluoroolefin andfrom 1 to 80 mol % of polymer units (4) having a polyoxyalkylene chainhaving a reactive group at its terminal, the total of the polymer units(1) and the polymer units (4) being from 30 to 100 mol %, and a compoundhaving a functional group reactive with the reactive group of thefluorine-containing copolymer and a functional group cross-linkable bythe action of moisture.

Further, the present invention provides a curable composition comprisinga curing agent and a fluorine-containing copolymer having fluidity atroom temperature and comprising, based on entire polymer units, from 20to 70 mol % of polymer units (1) derived from a fluoroolefin and from 1to 80 mol % of polymer units (2') having a polyoxyalkylene chain having,at its terminal group, a group selected from the group consisting of anactive hydrogen-containing group and an epoxy group, the total of thepolymer units (1) and the polymer units (2') being from 30 to 100 mol %.

Still further, the present invention provides a curable compositioncontaining a fluorine-containing copolymer having fluidity at roomtemperature and comprising, based on entire polymer units, from 20 to 70mol % of polymer units (1) derived from a fluoroolefin and from 1 to 80mol % of polymer units (2') having a polyoxyalkylene chain having, atits terminal, a functional group cross-linkable by the action ofmoisture, the total of the polymer units (1) and the polymer units (2")being from 30 to 100 mol %.

Now, the present invention will be described in detail with reference tothe preferred embodiments.

The fluorine-containing copolymer of the present invention contains from20 to 70 mol % of polymer units (1) derived from a fluoroolefin. Thefluoroolefin is preferably a fluoroolefin having from 2 to 6 carbonatoms, more preferably from 2 to 4 carbon atoms, such astetrafluoroethylene, chlorotrifluoroethylene, trifluoroethylene,vinylidene fluoride, vinyl fluoride, hexfluoropropylene orpentafluoroethylene. Among them, a perfluoroolefin is most preferredwherein hydrogen is completely substituted by halogen. If the polymerunits derived from a fluoroolefin are less than 20 mol %, no adequateweather resistance will be obtained, and staining tends to besubstantial during the use for a long period of time, such beingundesirable. If the amount of the fluoroolefin exceeds 70 mol %, ittends to be difficult to obtain good elasticity or good adhesion toother materials, such being undesirable. It is particularly preferredthat the copolymer contains from 30 to 70 mol % of the polymer unitsderived from a fluoroolefin.

The fluorine-containing copolymer of the present invention furthercontains from 1 to 80 mol % of polymer units (2) having apolyoxyalkylene chain having, at its terminal, a group selected from thegroup consisting of an active hydrogen-containing group, an epoxy groupand a functional group cross-linkable by the action of moisture. Byvirtue of such specific polymer units (2), the cured product can be anelastomer having excellent elasticity. Here, the activehydrogen-containing group may be a hydroxyl group, a carboxylic acidgroup, an amino group, an acid amide group or a thiol group. Thefunctional group cross-linkable by the action of moisture may be anisocyanate group, a hydrolyzable silyl group or a thiol group. If theproportion of the polymer units (2) is too small, it becomes difficultto obtain a good elastomer. On the other hand, if the proportion is toolarge, the weather resistance or the stain resistance tends to be low.It is particularly preferred that the copolymer contains from 3 to 30mol % of the polymer units (2).

The polymer units (2) may be those wherein the polyoxyalkylene chains asside chains are comprised solely of ether bonds and carbon-carbon bonds,or those which contain other bonds such as urethane bonds, ester bons oramino bonds between the main chain and the polyoxyalkylene chain. Thepolyoxyalkylene chain may be the one having at least two oxyalkyleneunits. If the number of oxyalkylene units is small, it tends to bedifficult to obtain a desired elastomer. The larger the number of theoxyalkylene units, the better the elasticity of the elastomer. However,if it is too much, the weather resistance or stain resistance tends tobe low. It is usually preferred that the number of oxyalkylene units isat most 50, more preferably at most 40. The oxyalkylene units arepreferably oxyalkylene units having from 2 to 8 carbon atoms such asoxyethylene units, oxypropylene units or oxybutylene units. Suchoxyalkylene chain may be composed of oxyalkylene units of the same typeor oxyalkylene units of a plurality of different types. If oxyalkyleneunits having a small carbon number are used alone as the oxyalkyleneunits, the water resistance tends to be low. On the other hand, idoxyalkylene units having a large carbon number are used alone, the oilresistance tends to be low. It is particularly preferred to employ apolyoxyalkylene chain composed mainly of oxyalkylene units having from 3to 6 carbon atoms. The oxyalkylene units may be those wherein a part ofhydrogen bonded to carbon is substituted by halogen such as fluorine orchlorine, or by an alkyl group or an aryl group. Further, when thefluorine-containing copolymer of the present invention is used as a basefor an elastic coating material, it is preferred to employ apolyoxyalkylene chain having at least five oxyalkylene units. Likewise,when the copolymer is used as a sealant base, it is preferred to employa polyoxyalkylene chain having at least ten oxyalkylene units.

As mentioned above, this polyalkylene chain has, at its terminal, anactive hydrogen-containing group, an epoxy group or a functional groupcross-linkable by the action of moisture. Such an activehydrogen-containing group, an epoxy group or a functional groupcross-linkable by the action of moisture, may be bonded directly to theterminal of the polyoxyalkylene chain, or may be bonded via other bondsuch as a urethane bond or an ester bond.

The fluorine-containing copolymer of the present invention may furthercontain other polymer units in addition to the above-described polymerunits (1) and (2). In such a case, the total of the polymer units (1)and the polymer units (2) is from 30 to 100 mol % based on the entirepolymer units. If the proportion of the polymer units (1) and (2) is toosmall, no adequate weather resistance, stain resistance and elasticitycan be obtained. Here, other polymer units may be polymer units derivedfrom a monomer copolymerizable with the fluoroolefin. The monomercopolymerizable with the fluoroolefin, may be an ethylenicallyunsaturated compound such as a vinyl compound, an allyl compound, anacryloyl compound or a methacryloyl compound. When polymer units otherthan the polymer units (1) and (2) are contained, a larger amount ofpolymer units will be contained among the polymer units (2), whereby theelasticity will be obtained more effectively.

The fluorine-containing copolymer of the present invention has fluidityat room temperature. Specifically, it preferably has fluidity at a levelsuch that it is deformable by its own weight at 25° C. Morespecifically, it preferably has a viscosity of at most 100,000centipoise (hereinafter referred to simply as cp) at 25° C. Afluorine-containing copolymer having a viscosity being too high isundesirable since the practical applicability is thereby extremely lowin its application to e.g. a sealant. A copolymer having a viscosity ofat most 20,000 cp at 25° C. is particularly preferred, since it providesexcellent practical applicability even when used without any solvent.There is no particular limitation to the lower limit of the viscosity.However, it is usual to employ a fluorine-containing copolymer having atleast 300 cp at 25° C.

The fluorine-containing copolymer of the present invention can beprepared by e.g. the following processes.

Firstly, there may be mentioned a process which comprises polymerizing afluoroolefin and a monomer having a polyoxyalkylene chain having, at itsterminal, a group selected from the group consisting of an activehydrogen-containing group, an epoxy group and a functional groupcross-linkable by the action of moisture, and an α,β-unsaturated groupcopolymerizable with the fluoroolefin.

Secondly, there may be mentioned a process which comprisesaddition-reacting an alkylene oxide to a fluorine-containing copolymer(hereinafter referred to as a fluorine-containing copolymer X)comprising, based on entire polymer units, from 20 to 70 mol % ofpolymer units derived from a fluoroolefin and from 1 to 80 mol % ofpolymer units (3) having a functional group to which an alkylene oxideis to be added, the total of the polymer units (1) and the polymer units(3) being from 30 to 100 mol %.

Thirdly, there may be mentioned a process which comprises reacting afluorine-containing copolymer (hereinafter referred to as afluorine-containing copolymer Y) comprising, based on entire polymerunits, from 20 to 70 mol % of polymer units (1) derived from afluoroolefin and from 1 to 80 mol % of polymer units (4) having apolyoxyalkylene chain having a reactive group at its terminal, the totalof the polymer units (1) and the polymer units (4) being from 30 to 100mol % with a compound having a functional group reactive with thereactive group of the fluorine-containing copolymer Y and a functionalgroup cross-linkable by the action of moisture.

In the first process, the monomer having a polyoxyalkylene chain havingat its terminal, an active hydrogen-containing group, an epoxy group ora functional group cross-linkable by the action of moisture and anα,β-unsaturated group copolymerizable with the fluoroolefin, maypreferably be a monomer having an α,β-unsaturated group, such as a vinylgroup, an allyl group, an acryloyl group or a methacryloyl group. Such amonomer may be prepared by a method which comprises addition-reacting analkylene oxide to a hydroxyl group-containing monomer such as ahydroxyalkylene ether, a hydroxyalkylallyl ether, a reaction product ofacrylic acid with a polyhydric alcohol, a reaction product ofglycidylallyl ether with an alkanol amine or a phenol compound or allylalcohol, or a method which comprises reacting a monomer having areactive group such as a hydroxyl group, an alkoxysilyl group, an epoxygroup or an amino group with a polyoxyalkylene compound having a groupreactive with the above reactive group, such as an isocyanate group, analkoxysilyl group or a carboxylic acid group. Further, it may beobtained by a method which comprises reacting to the monomer obtained bysuch a method, a compound having a functional group curable by theaction of moisture, such as a diisocyanate compound, an isocyanatealkylsilane compound, a silylisocyanate compound or a mercaptoalkanoicacid. In this first process, if only one type of the fluoroolefin andonly one type of the monomer having a polyoxyalkylene chain arepolymerized, it is highly likely that they undergo alternatingcopolymerization. Particularly when the monomer having a polyoxyalkylenechain is a vinyl compound or an allyl compound, this possibility isextremely high. In the case of alternating copolymerization, otherpolymerization units present between polymer units (2) will be as littleas only about one, whereby the resulting polymer tends to hardly havegood flexibility or elasticity. It is preferred to employ at least twodifferent kinds of compounds for either one or both of the fluoroolefinand the monomer having a polyoxyalkylene chain. Otherwise, in additionto the fluoroolefin and the monomer having a polyoxyalkylene chain,other comonomer copolyermizable therewith, may be copolymerized so thata number of such other polymer units will be present among the polymerunits (2) in the resulting polymer. Usually, the latter method ofcopolymerizing a comonomer is employed. Here, the commoner may be acompound having a pulverizable site such as a vinyl group, an allylgroup, an acryloyl group or a methacryloyl group. Specifically, olefins,vinyl ethers, vinyl esters, allyl ethers, allyl esters, acrylic acidesters and methacrylic acid esters may be mentioned. Particularlypreferred is a compound having a linear, branched or alicyclic alkylgroup having from 1 to 15 carbon atoms. Such a commoner may be the onewherein a part or all of hydrogen bonded to carbon is substituted byfluorine. In this first process, the proportion of the polymer units (1)is from 20 to 70 mol %, and the proportion of the polymer units (2) isfrom 1 to 80 mol %, and the total of the polymer units (1) and thepolymer units (2) is preferably at least 30 mol %, based on the entirepolymer units. Such polymerization may be conducted by any one ofsolution polymerization, emulsion polymerization, suspensionpolymerization and bulk polymerization. A polymerization initiator or apolymerization initiating source such as ionizing radiation is appliedto the predetermined amounts of monomers to conduct the polymerization.Various other conditions may be similar to those commonly employed forsolution polymerization, emulsion polymerization, suspensionpolymerization or bulk polymerization.

In the second process, the fluorine-containing copolymer X can beprepared by copolymerizing a fluoroolefin, a monomer having a functionalgroup to which an alkylene oxide can be added or a group convertible tosuch a functional group, and if necessary, other comonomer. Here, ahydroxyl group or a carboxyl group is a typical example for thefunctional group to which an alkylene oxide can be added. Here, themonomer having such a functional group or a group convertible to such afunctional group, includes a hydroxyalkyl vinyl ether, a hydroxyalkylallyl ether, a hydroxyalkyl vinyl ester, a hydroxylakyl allyl ester, aglycidyl vinyl ether, a glycidyl allyl ether, an aminoalkyl vinyl ether,an aminoalkyl allyl ether, an aminoalkyl vinyl ester, an aminoalkylallyl ether, acrylic acid, methacrylic acid and allyl vinyl ether. Asthe group convertible to the functional group to which an alkylene oxidecan be added, an ester group hydrolyzable after the polymerization, maybe mentioned. Further, if necessary, it may be converted to otherfunctional group to which an alkylene oxide can be added, afterpolymerization. For example, there may be mentioned a method wherein apolybasic carboxylic acid or its anhydride is added to a hydroxyl groupto convert it to a carboxylic acid group, or a method wherein an alkanolamine or a phenol compound is reacted to an epoxy group to convert it toa hydroxyl group. In the preparation of the fluorine-containingcopolymer X, a monomer similar to the comonomer described with respectto the above first process, may be copolymerized. In this case, it ispreferred to control the polymerization so that the proportion of thepolymer units (1) will be from 20 to 70 mol %, the proportion of thepolymer units (3) will be from 1 to 80 mol %, and the total of thepolymer units (1) and the polymer units (3) will be from 30 to 100 mol%, based on the entire polymer units of the copolymer. For thepolymerization, a method of polymerization similar to the one describedwith respect to the first process, may be employed. The addition of analkylene oxide to the fluorine-containing copolymer X thus prepared, canbe conducted in the same manner as the production of a usual polyethercompound.

In the third process, the fluorine-containing copolymer Y can beprepared by the following methods.

Firstly, there may be mentioned a method which comprises polymerizing afluoroolefin and a monomer copolymerizable with a fluoroolefin andhaving a polyoxyalkylene chain having a reactive group at the terminal.

Secondary, there may be mentioned a method which comprises reacting afluorine-containing copolymer Y' comprising from 20 to 70 mol % ofpolymer units (1) derived from a fluoroolefin and from 10 to 80 mol % ofpolymer units (5) having a reactive group, the total of the polymerunits (1) and the polymer units (5) being at least 30 mol %, based onentire polymer units, and a polyoxyalkylene compound having a groupreactive with the reactive group of the fluorine-containing copolymerY'.

Thirdly, there may be mentioned a method which comprisesaddition-reacting an alkylene oxide to the fluorine-containing copolymerY" comprising from 20 to 70 mol % of polymer units (1) derived from afluoroolefin and from 1 to 80 mol % of polymer units (6) having ahydroxyl group, the total of the polymer units (1) and the polymer units(6) being at least 30 mol %, based on entire polymer units.

The first method may be conducted in the same manner as described withrespect to the above first process.

The fluorine copolymer Y' in the second method can be prepared inaccordance with the method for the production of the fluorine-containingcopolymer X in the above-mentioned second process. Further, thepolyoxyalkylene compound capable of reacting with thefluorine-containing copolymer Y', can be prepared by a method whichcomprises reacting a compound such as an alkanol amine, a polyvalentisocyanate compound, an isocyanate alkyl acrylate, a silyl isocyanate ora polybasic carboxylic anhydride to a polyoxyalkylene having an alkyleneoxide added in accordance with a usual method, or a method whichcomprises adding an alkylene oxide by a usual method to a compound suchas a hydroxyalkyl vinyl ether.

The third method may be conducted in the same manner as the secondprocess descried above.

In the third method, the reactive group in the fluoride-containingcopolymer Y may be a hydroxyl group, a carboxylic acid, group, an aminogroup, an acid amide group, a thiol group, an active halogen-containinggroup, an epoxy group or an ethylenically unsaturated group. Thecompound having a functional group cross-linkable by the action ofmoisture, to be reacted to the fluorine-containing copolymer Y includes,for example, a polyvalent isocyanate compound such as hexamethylenediisocyanate or toluene diisocyanate, an isocyanate alkylsilane compoundsuch as γ-isocyanate proplymethyldimethoxysilane, a silylisocyanatecompound such as trimethoxysilyl isocyanate, a hydrolyzable silylgroup-containing compound such as 4-trimethoxysilyltetrahydropthalicanhydride, or a thiol group-containing compound such as a mercaptoalkanoic acid or a thiodialkanoic acid. The reaction of thefluorine-containing copolymer Y and the above compound, is preferablyconduced by reacting an excess equivalent of the above-mentionedcompound to the reactive group in the fluorine-containing copolymer Y.If the amount of the above compound to be reacted is small, gellation islikely to result, such being undesirable. It is particularly preferredto react at least one mol of the above identified compound per mol ofthe reactive group in the fluorine-containing copolymer Y.

The fluorine-containing copolymer of the present invention is suitablefor use as a base for e.g. a sealant or an elastic coating material.

Among the fluorine-containing copolymers of the present invention, onehaving an active hydrogen-containing group or an epoxy group at theterminal of the polyoxyalkylene chain (hereinafter referred to as afluorine-containing copolymer (a)) ma be combined with a curing agent toobtain a curable composition (hereinafter referred to as a composition(a)). Likewise, among the fluorine-containing copolymers of the presentinvention, one having a functional group cross-linkable by the action ofmoisture at the terminal of the polyoxyalkylene chain (hereinafterreferred to as a fluorine-containing copolymer (b)) makes a curablecomposition (hereinafter referred to as a composition (b)) even withoutincorporating a curing agent. Hereinafter, the composition (a) and thecomposition (b) are generally referred to simply as a composition.Further, the curable composition (b) may contain a curing agent.

As the curing agent for the composition (a), a compound may be employedwhich is capable of reacting with the active hydrogen-containing groupor the epoxy group of the fluorine-containing copolymer (a) to form across-linkage. For example, a polyvalent isocyanate compound, anaminoplasto compound or a polyvalent amino compound may be mentioned.Among them, a polyol-modified polyisocyanate compound is preferred,since it presents a cured product having excellent elasticity. When apolyvalent isocyanate compound is used as the curing agent, curing canbe conducted with moisture, and the practical applicability isexcellent. In this case, from the viewpoint of the reactivity with anisocyanate group, it is particularly preferred to employ as thefluorine-containing copolymer (a) a copolymer having an activehydrogen-containing group, particularly, a hydroxyl group.

To the composition of the present invention, additives such as a filler,a curing catalyst, a solvent, a photo stabilizer, an ultravioletabsorber, a heat stabilizer, a leveling agent, a defoaming or a foamsuppressing agent, may be incorporated, as the case requires.

The filler includes reinforcing fillers such as fumed silica,precipitated silica, silicic anhydride, hydrous silicic acid and carbonblack, fillers such as calcium carbonate, magnesium carbonate,diatomaceous earth, calcined clay;, clay, talc, surface-treated aluminumhydroxide, magnesium hydroxide, titanium oxide, bentonite, organicbentonite, ferric oxide, zinc oxide, active zinc white, hydrogenatedcastro oil and silica balloons; and fibrous fillers such as asbestos,glass fibers and glass filaments. The filler may be incorporated in anamount of from 1 to 500 parts by weight per 100 parts by weight of thefluorine-containing copolymer.

When a curable composition having a high strength is desired to beproduced with such a filler, a good result can be obtained by using afiller selected from the group consisting of fumed silica, precipitatedsilica, silicic anhydride, hydrous silicic acid, carbon black,surface-treated fine calcium carbonate, calcined clay, clay and activezinc white in an amount of from 1 to 100 parts by weight per 100 partsby weight of the fluorine-containing copolymer. When a curablecomposition having good elongation with low strength is desired to beproduced, a good result can be obtained by using a filler selected fromthe group consisting of titanium oxide, calcium carbonate, magnesiumcarbonate, talc, ferric oxide, zinc oxide and silica balloons in anamount of from 5 to 200 parts by weight per 100 parts by weight of thefluorine-containing copolymer. These fillers may, of course, be employedalone or in combination as a mixture of two or more different kinds.

Now, the present invention will be described with reference to Examples.However, it should be understood that the present invention is by nomeans restricted to such specific Examples.

PREPARATION EXAMPLES 1 TO 4

Hydroxybutyl vinyl ether (HBVE) and potassium hydroxide (concentration:95%) were charged in the amounts as identified in Table 1 into astainless steel pressure resistant reactor having an internal capacityof 5 l and equipped with a stirrer. Propylene oxide (PO) was graduallyadded thereto, and the reaction with conducted under a pressure of 3kg/cm² at 110° C. for a predetermined period of time. The liquid therebyobtained was purified by synthetic magnesia to obtain a vinyl etherhaving a polyoxyalkylene chain. The mol amount of added PO in each vinylether is shown in Table 1.

                  TABLE 1                                                         ______________________________________                                               Prep.   Prep.     Prep.     Prep.                                             Example 1                                                                             Example 2 Example 3 Example 4                                  ______________________________________                                        HBVE (g) 1,200     580       454     312                                      Potassium                                                                              9         11        15      15                                       hydroxide (g)                                                                 PO (g)   1,800     2,900     4,540   4,690                                    Reaction time                                                                          2          4        12      18                                       (hr)                                                                          Mol amount                                                                             3         10        20      30                                       of added PO                                                                   ______________________________________                                    

EXAMPLES 1 TO 6 AND COMPARATIVE EXAMPLES 1 AND 2

Into a stainless steel pressure resistant reactor having an internalcapacity of 550 ml and equipped with a stirrer, 112 g of xylene, 112 gof ethonal, 1.6 g of potassium carbonate and 0.5 g ofazoisobutyronitrile were charged, and the monomer composition asidentified in Table 2 was thereby polymerized. The polymerization wasconducted by charging monomers other than chlorotrifluoroethylene (CTFE)or tetrafluoroethylene (TFE), then dissolved air was removed underreduced pressure after liquid was frozen by liquid nitrogen, thenintroducing CTFE or TFE, gradually raising the temperature, maintainingthe temperature at 65° C., continuing the polymerization reaction understirring for 10 hours, then cooling the reactor with water to terminatethe polymerization. The reactor was cooled to room temperature, and thenunreacted monomers were withdrawn, and the reactor was opened. Thepolymer solution was filtered, and then the solvent was removed by anevaporator to obtain a fluorine-containing copolymer. The hydroxyl value(KOH mg/g), the number average molecular weight, the glass transitiontemperature and the viscosity at 25° C., of the fluorine-containingcopolymer thus obtained, are shown in Table 2.

In the molecular weight measurement (by using G.P.C) of thefluorine-containing copolymer in each Example, no substantial peakcorresponding to the vinyl ether obtained in Preparation Examples 1 to4, was observed. This indicates that the vinyl ether having apolyoxypropylene chain has been copolymerized.

                                      TABLE 2                                     __________________________________________________________________________                                                   Comparative                                           Examples                Examples                                              1   2   3   4   5   6   1   2                          __________________________________________________________________________    Monomers (g)                                                                          CTFE           71  59  65  59  --  63  58  59                                 TFE            --  --  --  --  43  --  --  --                                 EVE            38  36  30  --  30  16  33  29                                 CHVE           --  --  --  63  --  --  --  --                                 HBVE           --  --  --  --  --  --  5.5 12                                 Vinyl ether of Prep. Example 2                                                               60  5.5 --  5.5 80  --  --  --                                 Vinyl ether of Prep. Example 3                                                               --  --  180 --  --  --  --  --                                 Vinyl ether of Prep. Example 4                                                               --  --  --  --  --  180 --  --                         Hydroxyl value (KOH mg/g)                                                                            28.4                                                                              8.4 28  8.4 37  19  27  57                         Number average molecular weight                                                                       6,000                                                                            20,000                                                                            6,000                                                                             20,000                                                                            6,000                                                                             6,000                                                                             6,000                                                                             20,000                     Glass transition temp. (° C.)                                                                 -20 -8  -68 10  -25 -68 18  20                         Viscosity at 25° C. (cp)                                                                      15,000                                                                            30,000                                                                            8,000                                                                             60,000                                                                            9,000                                                                             6,000                                                                             Non-                                                                              Non-                                                                      liquid                                                                            liquid                     __________________________________________________________________________

In Table 2, CTFE denotes chlorotrifluoroethylene, TFE denotestetrafluoroethylene, EVE denotes ethyl vinyl ether, CHVE denotescyclohexyl vinyl ether, and HBVE denotes hydroxybutyl vinyl ether.

EXAMPLE 7

Into a stainless steel pressure resistant reactor having an internalcapacity of 550 ml and equipped with a stirrer, 145 g of xylene, 145 gof ethanol, 33 g of EVE (ethyl vinyl ether), 5.5 g of HBVE (hydroxybutylvinyl ether), 1 g of potassium carbonate and 0.5 g of AIBN(azoisobutyronitrile) were charged, and dissolved air was removed bysolidification deaeration by means of liquid nitrogen. Then, 58 g ofCTFE (chlorotrifluoroethylene) was introduced, and the mixture wasgradually heated. The temperature was maintained at 65° C., and thereaction was continued under stirring. Ten hours later, the reactor wascooled with water to terminate the reaction. The reactor was cooled toroom temperature, and unreacted monomers were withdrawn. Then, thereactor was opened. The reaction solution was filtered, and then thesolvent was removed by an evaporator to obtain a fluorine-containingcopolymer.

Further, into a stainless steel pressure resistant reactor having aninternal capacity of 5 l and equipped with stirrer, 10 g of thisfluorine-containing copolymer and 6 g of potassium hydroxide having aconcentration of 95%, and 816 g of PO (propylene oxide) was graduallyadded. The reaction was conducted under a pressure of 3 kg/cm² at 110°C. for 10 hours, and a transparent brown liquid thereby obtained waspurified by synthetic magnesia to obtain the desired fluorine-containingcopolymer having a mol amount of added PO of 20 mol. The obtainedcopolymer had a hydroxyl value of 15 (KOH mg/g), a number averagemolecular weight of 10,000 as measured by GPC, a glass transitiontemperature of -25° C. and a viscosity of 12,000 cp at 25° C.

EXAMPLE 8

100 g of polyoxypropylene diol having a molecular weight of 1,000 and 15g of dimethylsilyl diisocyanate were mixed and reacted to obtain apolyoxypropylene having a terminal isocyanate group. To 100 g of thefluorine-containing copolymer obtained in Comparative Example 1, 30 g ofthis polyoxypropylene having a terminal isocyanate group was reacted toobtain a fluorine-containing copolymer having a polyoxyalkylene chain.This fluorine-containing copolymer had a viscosity of 16,000 cp at 25°C.

TEST EXAMPLES 1 TO 7 AND COMPARATIVE TEST EXAMPLES 1 AND 2

To the fluorine-containing copolymers obtained in Examples 1 to 7 andComparative Examples 1 and 2, a polyol-modified diisocyanate compound(Duranate D101, tradename, manufactured by Asahi Kasei) was added in anamount corresponding to NCO/OH =1, and 500 ppm of dibutyltin dilauratewas added as the catalyst to cure the composition. The cured product wastested for the breaking elongation, the breaking strength, the 50%modulus of elasticity, the surface adhesiveness and the weatherresistance, and the results are shown in Table 3.

TEST EXAMPLE 8

The fluorine-containing copolymer obtained in Example 8 was cured withmoisture. The cured product was tested for the breaking elongation, thebreaking strength, the 50% modulus of elasticity, the surfaceadhesiveness and the weather resistance, and the results are shown inTable 3.

COMPARATIVE TEST EXAMPLE 3

A cured product was prepared in the same manner as in Test Example 1except that instead of the fluorine-containing copolymer, apolyoxypropylene triol (hydroxyl value: 33.7 KOH mg/g) having amolecular weight of 5,000 was employed. This cured product was testedfor the breaking elongation, the breaking strength, the 50% modulus ofelasticity, the surface adhesiveness and the weather resistance, and theresults are shown in Table 3.

COMPARATIVE TEST EXAMPLE 4

A cured product was prepared in the same manner as in Test Example 1except that instead of the fluorine-containing copolymer, afluorine-containing copolymer prepared by adding 3 mols ofε-caprolactone per mol of the hydroxyl group of the fluorine-containingcopolymer of Comparative Example 1, was employed. The results of varioustests of this cured product are shown in Table 3.

COMPARATIVE TEST EXAMPLE 5

A commercially available modified silicone-type sealing material wastested for the breaking elongation, the breaking strength, the 50%modulus of elasticity, the surface adhesiveness and the weatherresistance, and the results are shown in Table 3.

                                      TABLE 3                                     __________________________________________________________________________              Test Examples                   Comparative Test Examples                     1   2   3   4   5   6   7   8   1   2   3   4   5                   __________________________________________________________________________    Fluorine-containing                                                                     Ex. 1                                                                             Ex. 2                                                                             Ex. 3                                                                             Ex. 4                                                                             Ex. 5                                                                             Ex. 6                                                                             Ex. 7                                                                             Ex. 8                                                                             Comp.                                                                             Comp.                                                                             --  --  --                  copolymer                                 Ex. 1                                                                             Ex. 2                           Breaking elongation                                                                     600 900 950 700 900 1,100                                                                             950 750 100 89  850 150 600                 (%)                                                                           Breaking strength                                                                       7   10  9   18  10  10  13  11  60  130 13  50  6.5                 (kg/cm.sup.2)                                                                 50% Modulus of                                                                          3   6   2   14  4   1.5 5   5   25  850 2   20  10                  elasticity                                                                    (kg/cm.sup.2)                                                                 Surface   0.4 0.2 0.5 0.1 0.3 0.4 0.3 0.4 0.1 0.05                                                                              2.0 0.2 0.6                 adhesiveness (kg)                                                             Weather resistance                                                            Surface condition                                                                       ◯                                                                     ◯                                                                     ◯                                                                     ◯                                                                     ◯                                                                     ◯                                                                     ◯                                                                     ◯                                                                     ⊚                                                                  ⊚                                                                  X   ⊚                                                                  ◯       Elongation                                                                              80  85  85  85  85  85  80  83  95  97  55  93  65                  retaining rate (%)                                                            __________________________________________________________________________

PREPARATION EXAMPLE 5

To 100 g of the vinyl ether having a polyoxyalkylene chain obtained inPreparation Example 3, 16 g of γ-isocyanate propylmethyl dimethoxysilanewas reacted in the presence of 0.01 g of dibutyltin dilaurate at roomtemperature under a nitrogen atmosphere for 4 hours under stirring toobtain a vinyl ether having a polyoxyalkylene chain having amethoxysilyl terminal group.

EXAMPLE 9

Into a glass container having an integral capacity of 300 ml, 16.8 g ofhexamethylene diisocyanate (hereinafter referred to simply as HDI) wasintroduced, and 200 g of the fluorine-containing copolymer of Example 3was gradually dropwise added thereto in a dry nitrogen gas stream understirring. Then, the reaction was continued for 24 hours, and theinfrared spectrum was measured, whereby it was confirmed that a half ofthe peak attributable to the isocyanate group of HDI was changed to aurethane bond. Then, the reaction was terminated by cooling to obtain216.8 g of the fluorine-containing copolymer having an isocyanate group.This fluorine-containing copolymer had a viscosity of 9,000 cp at 25° C.Then, 0.01 g of dibutyltin dilaurate was added to thisfluorine-containing copolymer, and the mixture was stored in a containerpurged with nitrogen, at 50° C. for 20 days. Then, the fluidity wasexamined, whereby no gellation was observed, and the fluidity wasexcellent. This fluorine-containing copolymer was coated in a thicknessof 1 mm and left to stand still in a room under a standard condition at20° C. under a relative humidity of 65%, whereby the copolymer cured in24 hours. This indicates that this fluorine-containing copolymer has onepack type room temperature curability.

EXAMPLE 10

Into a glass container having an integral capacity of 300 ml, 11.5 g ofHDI was introduced, and 200 g of the fluorine-containing copolymer ofExample 6 was gradually dropwise added thereto in a dry nitrogen gasstream under stirring. Then, the reaction was continued for 24 hours,and the infrared absorption spectrum was measured, whereby it wasconfirmed that a half of the peak attributable to the isocyanate groupof HDI was changed to a urethane bond. Then, the reaction was terminatedby cooling to obtain 211.5 g of a fluorine-containing copolymer havingan isocyanate group. This fluorine-containing copolymer had a viscosityof 8,000 cp at 25° C. Then, 0.01 g of dibutyltin dilaurate was added tothis fluorine-containing copolymer, and the mixture was stored in acontainer purged with nitrogen, at 50° C. for 20 days. Then, thefluidity was examined, whereby no gellation was observed, and thefluidity was excellent. This fluorine-containing copolymer was coated ina thickness of 1 mm and left to stand still in a room under a standardcondition at 20° C. under a relative humidity of 65%. The copolymercured in 24 hours. This indicates that this fluorine-containingcopolymer has one pack type room temperature curability.

COMPARATIVE EXAMPLE 3

A polymer having an isocyanate group was prepared in the same manner asin Example 9 except that instead of the fluorine-containing copolymer,200 g of a trifunctional polypropylene glycol having a molecular weightof 5,000 and 20.2 of HDI were used. This polymer was also found to haveone pack type room temperature curability.

EXAMPLE 11

Into a glass container having an integral capacity of 300 ml, 200 g ofthe fluorine-containing copolymer of Example 3, 20.4 g of γ-isocyanatepropylmethyldimethoxiysialne and 0.02 g of dibutyltin dilaurate as acuring catalyst were charged and stirred at room temperature under anitrogen atmosphere for 4 hours. The infrared absorption spectrum of thefluorine-containing copolymer thus obtained was measured, whereby it wasconfirmed that the absorption attributable to the isocyanate groupdisappeared, and an absorption peak attributable to a urethane bondappeared, and the copolymer had an alkoxysilyl group. Thisfluorine-containing copolymer had a viscosity of 8,500 cp at 25° C.Then, 1 g of dibutyltin dilaurate was added to this fluorine-containingcopolymer, and the mixture was stored in a container purged withnitrogen gas, at 50° C. for 20 days. Then, the fluidity was examined,whereby no gellation was observed, and the fluidity was excellent. Thisfluorine-containing copolymer was coated in a thickness of 1 mm and leftto stand still in a room under a standard condition at 20° C. under arelative humidity of 65%. the copolymer cured in 24 hours. Thisindicates that this fluorine-containing copolymer has one pack type roomtemperature curability.

EXAMPLE 12

Into a glass container having an integral capacity of 300 ml, 200 g ofthe fluorine-containing copolymer of Example 6, 14 g of γ-isocyanatepropylmethyldimethoxiysialne and 0.02 g of dibutyltin dilaurate as acuring catalyst were charged and stirred at room temperature under anitrogen atmosphere for 4 hours. The infrared absorption spectrum of thefluorine-containing copolymer thus obtained was measured, whereby it wasconfirmed that the absorption attributable to the isocyanate groupdisappeared, and an absorption peak attributable to a urethane bondappeared, and the copolymer had an alkoxysilyl group. Thisfluorine-containing copolymer had a viscosity of 8,000 cp at 25° C.Then, 1 g of dibutyltin dilaurate was added to this fluorine-containingcopolymer, and the mixture was stored in a container purged withnitrogen gas, at 50° C. for 20 days. Then, the fluidity was examined,whereby no gellation was observed, and the fluidity was excellent. Thisfluorine-containing copolymer was coated in a thickness of 1 mm and leftto standstill in a room under a standard condition at 20° C. under arelative humidity of 65%. the copolymer cured in 24 hours. Thisindicates that this fluorine-containing copolymer has one pack type roomtemperature curability.

COMPARATIVE EXAMPLE 4

A polymer having an isocyanate group was prepared in the same manner asin Example 11 except that instead of the fluorine-containing copolymer,200 g of a trifunctional polypropylene glycol having a molecular weightof 5,000 and 23 of γ-isocyanate proplymethyldimethoxysilane were used.This polymer had a viscosity of 6,000 cp at 25° C. This polymer also hadone pack type room temperature curability.

EXAMPLE 13

Into a glass container having an integral capacity of 300 ml, 200 g ofthe fluorine-containing copolymer having an isocyanate group of Example9 was introduced, and 18 g of γ-aminopropyltrimethyldimethoxysilane wasgradually dropwise added thereto in a dry nitrogen gas stream understirring. Then, the reaction was continued for 8 hours, and the infraredabsorption spectrum was measured, whereby it was confirmed that theabsorption attributable to the isocyanate group disappeared, and itchanged into a urea bond. Thus, a fluorine-containing copolymer havingan alkoxysilyl group was obtained. This fluorine-containing copolymerhad a viscosity of 11,000 cp at 25° C. Then, 1 g of dibutyltin dilauratewas added to this fluorine-containing copolymer, and the mixture wasstored in a container purged with nitrogen gas, at 50° C. for 20 days.Then, the fluidity was examined, whereby no gellation was observed, andthe fluidity was excellent. This fluorine-containing copolymer wascoated in a thickness of 1 mm and left to stand still in a room under astandard condition at 20° C. under a relative humidity of 65%. thecopolymer cured in 24 hours. This indicates that thisfluorine-containing copolymer has one pack type room temperaturecurability.

EXAMPLE 14

Into a glass container having an integral capacity of 300 ml, 200 g ofthe fluorine-containing copolymer having an isocyanate group of Example10 was introduced, and 12 g of γ-aminopropyltrimethyoxysilane wasgradually dropwise added thereto in a dry nitrogen gas stream understirring. Then, the reaction was continued for 8 hours, and the infraredabsorption spectrum was measured, whereby it was confirmed that theabsorption attributable to the isocyanate group disappeared, and itchanged into a urea bond. Thus, a fluorine-containing copolymer havingan alkoxysilyl group was obtained. This fluorine-containing copolymerhad a viscosity of 9,000 cp at 25° C. Then, 1 g of dibutyltin dilauratewas added to this fluorine-containing copolymer, and the mixture wasstored in a container purged with nitrogen gas, at 50° C. for 20 days.Then, the fluidity was examined, whereby no gellation was observed, andthe fluidity was excellent. This fluorine-containing copolymer wascoated in a thickness of 1 mm and left to stand still at roomtemperature under a standard condition at 20° C. under a relativehumidity of 65%. The copolymer cured in 24 hours. This indicates thatthis fluorine-containing copolymer has one pack type room temperaturecurability.

COMPARATIVE EXAMPLE 5

A polymer having an isocyanate group was prepared in the same manner asin Example 13 except that instead of the fluorine-containing copolymer,200 g of the polymer obtained in Comparative Example 3 and 21 g ofγ-aminopropylmethyldimethoxysilane were used. This polymer also had onepack type room temperature curability.

EXAMPLE 15

Into a glass container having an integral capacity of 300 ml, 200 g ofthe fluorine-containing copolymer of Example 3 was introduced, and 0.06g of triethylamine was added thereto. Then, 27.2 g of 4-trimethoxysilyltetrahydrophthalic anhydride was gradually dropwise added thereto in adry nitrogen gas stream at 50° C. Then, the reaction was continued for 5hours, and the infrared absorption spectrum was measured, whereby it wasconfirmed that the absorption peak attributable to the hydroxyl groupdisappeared, and a peak attributable to a carboxylic acid appeared,Then, the reaction was terminated by cooling to obtain 236.8 g of afluorine-containing copolymer having an alkoxysilyl group. Thisfluorine-containing copolymer had a viscosity of 9,500 cp at 25° C.Then, 1 g of dibutyltin dilaurate was added to this fluorine-containingcopolymer, and the mixture was stored in a container purged withnitrogen gas, at 50° C. for 20 days. Then, the fluidity was examined,whereby no gellation was observed, and the fluidity was excellent. Thisfluorine-containing copolymer was coated in a thickness of 1 mm and leftto stand still in a room under a standard condition at 20° C. under arelative humidity of 65%. the copolymer cured in 24 hours. Thisindicates that this fluorine-containing copolymer has one pack type roomtemperature curability.

COMPARATIVE EXAMPLE 6

A polymer having an isocyanate group was prepared in the same manner asin Example 14 except that instead of the fluorine-containing copolymer,200 g of a trifunctional polypropylene glycol having a molecular weightof 5,000 and 32.6 of 4-trimethoxysilyl tetrahydrophthalic anhydride wereused. This polymer was also found to have one pack type room temperaturecurability.

EXAMPLE 16

Into a glass container having an integral capacity of 300 ml, 200 g ofthe fluorine-containing copolymer having an isocyanate group of Example9 was introduced, and 5.8 g of allyl alcohol was gradually dropwiseadded in a dry nitrogen gas stream at 80° C. under stirring. Then, thereaction was continued for 24 hours. The infrared absorption spectrum ofthe reaction product was measured, whereby no peak attributable to theisocyanate group was detected, and a peak attributable to a urethanebond was detected. To 100 g of the fluorine-containing copolymer thusobtained, 8 g of β,β'-dimercaptodiethylether, 0.5 g of t-butylperbenzoate and 0.05 g of tetramethylguanidine were added, and themixture was slowly stirred and then left to stand still at 60° C. for 16hours. From the infrared spectrometry, it was confirmed that the producthad no double bond. This fluorine-containing copolymer had a viscosityof 13,000 cp at 25° C. To this fluorine-containing copolymer, 0.5 g oflead dioxide was added, and the fluidity was examined, whereby nogellation was observed, and the fluidity was excellent. Thisfluorine-containing copolymer was coated in a thickness of 1 mm and leftto stand still at room temperature under a standard condition at 20° C.under a relative humidity of 65%. the copolymer cured in 24 hours. Thisindicates that this fluorine-containing copolymer has one pack type roomtemperature curability.

EXAMPLE 17

Into a stainless steel pressure resistant container having an integralcapacity of 550 ml equipped with a stirrer, 112 g of xylene, 112 ofethanol, 1.6 g of potassium carbonate and 0.5 g of azoisobutyronitrilewere charged, and 194 g of the vinyl ether obtained in PreparationExample 5, 19 g of cyclohexyl vinyl ether and 11 of ethyl vinyl etherwere charged. Then, dissolved air was removed by means of liquidnitrogen. Then, 51 g of chlorotrifluoroethylene was introduced. Thetemperature was gradually raised and then maintained at 65° C., and thepolymerization reaction was continued under stirring for 10 hours. Thereactor was cooled with water to terminate the polymerization. Then, thereactor was cooled to room temperature, unreacted monomers werewithdrawn, and the reactor was opened. The polymer solution wasfiltered, and then the solvent was removed by an evaporator to obtain afluorine-containing copolymer. The obtained fluorine-containingcopolymer had a number average molecular weight of 6,500, a glasstransition temperature of -68° C. and a viscosity of 9,000 cp at 25° C.In the molecular weight measurement, (by means of G.P.C.). of thisfluorine-containing copolymer, no substantial peak corresponding to thevinyl ether obtained in Preparation Example 5 was observed. Thisindicates that the vinyl ether having the polyoxyalkylene chain wascopolymerized.

TEST EXAMPLES

To 100 g of each of the fluorine-containing copolymers obtained inExamples 8 to 17 and Comparative Examples 3 to 6, the curing catalyst,titanium oxide and calcium carbonate were added as identified in Table4, and the mixture was coated in a thickness of 2 m on a stainless steelplate and left to stand at 20° C. under a relative humidity of 65%. Withrespect to the films thus obtained, the breaking elongation (%), thebreaking strength (kg/cm²), the 50% modulus of elasticity, the surfaceadhesiveness and the weather resistance were evaluated. The results areshown in Table 4.

                                      TABLE 4                                     __________________________________________________________________________               Test Examples                       Comparative Test Examples                 9   10  11  12  13  14  15  16  17  3   4   5   6                  __________________________________________________________________________    Fluorine-containing                                                                      Ex. 9                                                                             Ex. 10                                                                            Ex. 11                                                                            Ex. 12                                                                            Ex. 13                                                                            Ex. 14                                                                            Ex. 15                                                                            Ex. 16                                                                            Ex. 17                                                                            Comp.                                                                             Comp.                                                                             Comp.                                                                             Comp.              copolymer                                      Ex. 3                                                                             Ex. 4                                                                             Ex.                                                                               Ex. 6              Curing catalyst 1 (g)                                                                    0.01                                                                              0.01                                                                              1.0 1.0 1.0 1.0 1.0 --  0.01                                                                              1.0 1.0 1.0 1.0                Curing catalyst 2 (g)                                                                    --  --  --  --  --  --  --  0.5 --  --  --  --  --                 Titanium oxide (g)                                                                       4   4   4   4   4   4   4   4   4   4   4   4   4                  Calcium carbonate (g)                                                                    76  76  76  76  76  76  76  76  76  76  76  76  76                 Breaking elongation                                                                      300 500 400 700 400 600 350 450 450 350 400 400 400                (%)                                                                           Breaking strength                                                                        17  15  17  16  18  17  14  15  16  14  15  16  13                 (kg/cm.sup.2)                                                                 50% Modulus of                                                                           5   3   4   2   5   3   4   2   3   4   3   4   3                  elasticity                                                                    (kg/cm.sup.2)                                                                 Surface adhesiveness                                                                     0.2 0.3 0.1 0.2 0.2 0.3 0.1 0.1 0.1 1.5 1.2 1.0 1.0                (kg)                                                                          Weather resistance                                                            Surface condition                                                                        ⊚                                                                  ◯                                                                     ⊚                                                                  ⊚                                                                  ⊚                                                                  ◯                                                                     ⊚                                                                  ◯                                                                     ⊚                                                                  X   X   X   X                  Elongation 85  80  90  85  85  80  85  80  92  50  55  50  55                 retaining rate (%)                                                            __________________________________________________________________________     Curing catalyst 1 is dibutyltin dilaurate                                     Curing catalyst 2 is lead dioxide                                        

In each Test Example, the breaking elongation, the breaking strength andthe 50% modulus elasticity were measure in accordance with JIS K6301.The surface adhesiveness was measured under a load of 100 g by means ofa Pictamac (manufactured by Toyo Seiki). The weather resistance wasevaluated by the surface condition (⊚: no change, ○: no substantialproblem although some decrease in gloss was observed, X: substantialdeterioration in the surface condition) and the elongation retainingrate (breaking elongation after the weather resistant test/initialbreaking elongation x 100 (%)) after 1,000 hours of sunshineweather-o-meter test.

What is claimed is:
 1. A curable composition comprising a curing agentand a fluorine-containing copolymer having fluidity at room temperatureand comprising, based on entire polymer units, from 20 to 70 mol % ofpolymer units (1) derived from a fluoroolefin and from 1 to 80 mol % ofpolymer units (2') having a polyoxyalkylene chain having, at itsterminal, a group selected from the group consisting of an activehydrogen-containing group, an epoxy group, the total of the polymerunits (1) and the polymer units (2') being from 30 to 100 mol %.
 2. Thecurable composition according to claim 1, wherein the activehydrogen-containing group is a group selected from the group consistingof a hydroxyl group, a carboxylic acid group, an amino group, a thiolgroup and an acid amide group.
 3. The curable composition according toclaim 1, wherein the active hydrogen-containing group is a hydroxylgroup.
 4. The curable composition according to claim 1, wherein thepolyoxyalkylene chain is a polyoxyalkylene chain having from 5 to 50oxyalkylene units.
 5. The curable composition according to claim 1,wherein the polyoxyalkylene chain is composed of oxyalkylene unitshaving from 2 to 8 carbon atoms.
 6. The curable composition according toclaim 1, wherein the fluorine-containing copolymer has a viscosity offrom 300 to 100,000 centipoise at 25° C.
 7. The curable compositionaccording to claim 1, wherein the curing agent is a polyvalentisocyanate compound or an aminoplasto compound.
 8. The curablecomposition according to claim 1, wherein the curing agent is apolyvalent isocyanate compound.
 9. The curable composition according toclaim 1, wherein the curing agent is a polyol-modified polyisocyanate.10. The curable composition according to claim 1, which further containsa filler.
 11. The curable composition according to claim 10, wherein thefiller is contained in an amount of from 1 to 500 parts by weight per100 parts by weight of the fluorine-containing copolymer.
 12. Thecurable composition according to claim 10, wherein the filler isselected from the group consisting of fumed silica, precipitated silica,silicic anhydride, hydrous silicic acid, carbon black, surface-treatedfine calcium carbonate, surface-treated aluminum hydroxide, calcinedclay, clay, titanium oxide, calcium carbonate, magnesium carbonate,talc, ferric oxide, zinc oxide and silica balloons.
 13. A curablecomposition containing a fluorine-containing copolymer having fluidityat room temperature and comprising, based on entire polymer units, from20 to 70 mol % of polymer units (1) derived from a fluoroolefin and from1 to 80 mol % of polymer units (2") having a polyoxyalkylene chainhaving, at its terminal, a functional group cross-linkable by the actionof moisture, the total of the polymer units (1) and the polymer units(2") being from 30 to 100 mol %.
 14. The curable composition accordingto claim 13, wherein the functional group cross-linkable by the actionof moisture is a group selected from the group consisting of anisocyanate group, a hydrolyzable silyl group and a thiol group.
 15. Thecurable composition according to claim 13, wherein the polyoxyalkylenechain is a polyoxyalkylene chain having from 5 to 50 oxyalkylene units.16. The curable composition according to claim 13, wherein thepolyoxyalkylene chain is composed of oxyalkylene units having from 2 to8 carbon atoms.
 17. The curable composition according to claim 13,wherein the fluorine-containing copolymer has a viscosity of from 300 to100,000 centipoise at 25° C.
 18. The curable composition according toclaim 13, which further contains a filler.
 19. The curable compositionaccording to claim 18, wherein the filler is contained in an amount offrom 1 to 500 parts by weight per 100 parts by weight of thefluorine-containing copolymer.
 20. The curable composition according toclaim 18, wherein the filler is selected from the group consisting offumed silica, precipitated silica, silicic anhydride, hydrous silicicacid, carbon black, surface-treated fine calcium carbonate, calcinedclay, clay, titanium oxide, magnesium carbonate, talc, ferric oxide,zinc oxide and silica balloons.